<!doctype html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="https://cdn.tailwindcss.com"></script>
    <title></title>
    <script>
        // https://segmentfault.com/a/1190000014116655 剧中实现
    </script>


</head>
<body>
<div style="">
  <div style="width: 400px; height: 200px;" class="bg-blue-400">
      <div class="bg-red-200 w-10 h-10 mx-auto">

      </div>
  </div>

    <hr>
    <div style="width: 400px; height: 200px; vertical-align: middle" class="bg-blue-400 inline-block">
        <div class="bg-red-200 w-10 h-10 mx-auto" style="vertical-align: middle">

        </div>
    </div>

</div>

</body>
</html>